摘要
近年来北京大气中CH4含量仍在上升 ,但平均增长率已从 1985～ 1989年的 1 76 %·a- 1 ,下降到 1990～ 1997年的 0 50 %·a- 1 ;冬季和夏季两次出现峰值 ,表现出明显的双峰模态季节变化。但北京大气CH4变化的最大特点是年际季变化不均一 ,12年中 ,北京大气CH4共计增长185× 10 - 9混和体积比 ,其中冬季增长的贡献为 6 9× 10 - 9混和体积比 ,约占总增长的 37% ;而夏季的增长贡献不足 4 0× 10 - 9混和体积比 ,约占总增长的 2 1%。 90年代以后 ,北京大气CH4增长率进一步减慢 ,主要原因是生物源排放不再增加 ,而非生物源排放量的增长是大气CH4继续增长的主要原因。
The atmospheric methane in Beijing is still increasing, although its increasing rate has significantly decreased from 1 76%·a -1 during 1985～1989 to 0 50%·a -1 during 1990～1997 The seasonal variation of methane concentration has shown a double-peak pattern, one peak appearing in winter and the other in summer It is evident that the annually seasonal variations of atmospheric methane in Beijing are different From 1986 to 1997, the atmospheric methane increased by 185 ppbv, 37% and 21% of which were due to the increase in winter and in summer, respectively After 1993, the annually seasonal increasing rate of methane concentration in summer (due to emission from biogenic sources) is negative while the increasing rate in winter (due to emission from non-biogenic sources) is positive about 25 ppbv·a -1 As a result, the increase of methane emission from non-biogenic sources in winter is the major cause of the annually seasonal increasing rate from 1993 to 1997 The biogenic sources in Beijing are shrinking while the non-biogenic ones (such as fossil fuel combustion) are enlarging
出处
《大气科学》
CSCD
北大核心
2000年第2期157-164,共8页
Chinese Journal of Atmospheric Sciences
基金
中国科学院"九五"重大项目!"大气污染预测的理论和方法研究" (KZ951 -A1 -4 0 3 )
中国科学院大气物理研究所所长基金支持项目
关键词
甲烷
增长率
季节变化
年际季变化
大气
atmospheric methane
increasing rate
seasonal variation
annually seasonal variation
